package com.zjj.algorithm.learning.niuke;

import java.util.Scanner;

/**
 * @author zjj_admin
 * @date 2023/2/9 21:02
 */
public class Test53 {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int[] nums = new int[n + 1];
        nums[n - 1] = 1;
        for (int i = 1; i < n; i++) {
            int[] nums2 = new int[n + 1];
            for (int j = 0; j < n + 1; j++) {
                nums2[j] += nums[j];
                if (j - 1 >= 0) {
                    nums2[j] += nums[j - 1];
                }
                if (j + 1 < nums.length) {
                    nums2[j] += nums[j + 1];
                }
//                int sum = 0;
//                for (int k = 0; k < j; k++) {
//
//                    sum += nums2[k];
//
//                }
            }
            nums = nums2;
        }
        int count = -2;
        for (int i = 0; i < nums.length - 1; i++) {
            if (nums[i] % 2 == 0) {
                count = i;
                break;

            }
        }
        System.out.println(count + 1);

    }
}
